What you may be doing wrong when working your abs

A few weeks ago I began a series about a dire and complicated problem in the fire service: back injuries. If you haven’t seen it yet (it’s posted on every page of this series), the video below is a good primer about the misconceptions we have about treating and preventing back pain and injuries. Each week I’m going more in depth about the 6 myths discussed in this video. (see myth #1: back injuries are rare; myth 2: you need a flexible back to avoid back injury; myth #3: you need a strong back to avoid injury; and myth #4: you should bend your knees when you lift). I will discuss myth #5 below the video.

Myth #5: You should suck in your belly to work your core

In this myth, Dr. McGill states that you should avoid “sucking in your belly” and instead “stiffen the abdominal wall.” Those instructions may resonate really well with some people, but to me, those two things seem like pretty much the same thing in practice (because when I contract/stiffen my abdominal wall, my belly button moves posteriorly/backward). In situations when I’ve been given those instructions, or given them to others, I felt they were just a way to help people visualize what it vaguely feels like to contract your abs, and were not meant to be taken literally.

Nonetheless, as McGill is pointing out, the position of your spine during abdominal exercises is crucial, so it’s important to get it right. Although the best exercises for the core are done on the hands and toes (like a plank) it’s still popular to work your abs lying on your back. When doing so, don’t try to push your low back completely into the floor but, equally important, avoid arching your back.

If you’re really into crunches, be aware that very little movement actually needs to occur to work your abs. You really should only lift your shoulder blades off the ground. If you’re yarding your torso off the floor you’re likely using all sorts of muscles besides your abs and compressing your spine too much. situps edited See, in the picture to the right, how the spine is neutral in the starting position; the abs are contracted but the back is not pressed into the floor. You really should never do sit-ups as they’re bad for your back.

I should also mention that other highly educated professionals in my field very much believe that activating the transverse abdominus is important for improved core strength/spine health. Sometimes we scientists disagree simply because various research studies produce conflicting results or have different methodologies (which can mask the reasons for conflicting findings.)

Over the next few weeks I’ll be discussing more myths about back injuries in firefighters, plus I’ll show you some exercises that you may unknowingly be doing that are BAD for your back!

Other myths in this series:

Myth #6: sit-ups/crunches will give you a six-pack

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By | 2018-06-01T07:21:21+00:00 April 16th, 2014|Uncategorized|2 Comments

About the Author:

Dr. Karlie Moore has a PhD in Exercise Science and Nutrition and specializes in firefighter health. She has conducted fitness testing on hundreds of firefighters and has created the most comprehensive online wellness program for fire departments called the FitCulture program. Dr. Moore is also married to a firefighter and so understands their lifestyle and the health challenges associated with it.


  1. Steve West April 23, 2014 at 4:43 am

    I really appreciate the information you provide; it will be very difficult to remove the sit up from mainstream practice but I for one have stopped doing it.


    • Karlie April 23, 2014 at 4:12 pm

      Awesome Steve, I’m glad you’re benefiting from it!

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